Field of the Invention
The present invention relates to a printing apparatus which prints a code on a media such as a printing apparatus which can be used for an inkjet type printing apparatus which performs printing by ejecting ink, and to a printing method.
Description of the Related Art
A printing apparatus which performs printing by ejecting ink from a moving print head is used in printing in a wide variety of fields. Moreover, in recent years, printing of a two-dimensional code on a media has been performed by using such a printing apparatus.
In printing of a two-dimensional code, it should have such a printing quality that a reader accurately and rapidly recognizes and does not misread it. Specifically, it is necessary that (1) density contrast between a white part (non-printed part) and a black part (printed part) is high; and (2) a density change at a boundary between the white part and the black part is sharp. Moreover, it is necessary that (3) arrangement of each component, element, and cell is accurate; and (4) a position detection pattern of the two-dimensional code is printed without deficiency.
In printing in the inkjet printing apparatus which performs printing by ejecting ink while moving the print head, the ejected ink is ejected after being separated to a main droplet and a sub droplet. Thus, in a case where the sub droplet adheres much to the white part in printing of the two-dimensional code, the reader recognizes that a region of the white part is small, and reading accuracy lowers in some cases. Moreover, in the inkjet printing apparatus, one two-dimensional code is printed by a plurality of times of scanning in some cases. In this case, a shift occurs at a boundary in printing for each scanning in some cases, and reading accuracy lowers in some cases due to variation in a movement amount when the print head moves or variation in a conveyance amount of the media.
The lowering of reading accuracy caused by the sub droplet generated at ejection of the ink can be suppressed by the method of Japanese Patent Laid-Open No. 2005-47168, but the lowering of the code information reading accuracy caused by the shift of printing positions of an image cannot be suppressed, which remains to be a problem.